Image by BeyondDC licensed under Creative Commons.

This post is the first of a series covering questions and benefits of Accessory Apartments.

Advocates fought long and hard for accessory apartments in DC, which are additional housing units such as an English basement or carriage house that can be rented out to a tenant. Now that they’re finally becoming a reality, we thought it would be useful address challenges that come up from people who are going through the process of creating one of these units of their own. First, here's an overview of what accessory apartments are, and how they can be beneficial.

As I have written before, DC’s new zoning regulations allow for the by-right (meaning no special zoning exceptions are necessary) development of Accessory Apartments (also known as Accessory Dwelling Units, or ADUs) in the city’s residential zones. This means that homeowners in these zones can build an additional unit on their property, which are typically situated inside the principal dwelling unit (usually in a basement) or as a separate, freestanding structure on the lot.

Allowing accessory apartments to be built as a matter-of-right is a good thing because they provide a number of benefits at the city, neighborhood, and individual levels. For one, accessory apartments contribute to housing affordability by increasing the overall supply of housing. They also increase density without significantly changing neighborhood character.

I will follow posts about the benefits of accessory apartments in the context of housing affordability and accessibility, but first I am going to focus on the wide-ranging benefits of accessory apartments for individual households, especially as they change over time.

As demonstrated in this video, accessory apartments can serve many different purposes, meaning that their use can vary between households, and also that they can be used differently by individual households as they change over time.

For instance, the video gives the example of a household who chooses to build an accessory apartment when they begin to have children. The homeowners see the rental revenue that can be generated by an accessory apartment as a source of extra cash that can be used for savings for college and retirement.

However, as the household’s needs change over time, the accessory apartment provides other benefits as well. In this case, after the accessory apartment had generated its intended financial benefits, an aging family member moved in.

For another household, the accessory apartment provides income and reduced living expenses as the homeowner enters retirement. In this case, the homeowner, who no longer needed the amount of space in the principal unit, chose to build an occupy the accessory apartment while renting out the principal unit. The financial benefits related to the accessory apartment provided the homeowner with the resources needed to support her changing lifestyle.

The fact that accessory apartments can provide a number of benefits for different households, and for individual households as their needs change over time, means that developing accessory apartments might be an attractive option for many homeowners. This is a good thing, because if built at a sufficient scale, these units will provide broader benefits to both neighborhoods and to the city, as well as to the individual.

If you are interested in learning more about accessory apartments and the rules in DC, or if you have a question or experience you’d like to share, please check out the DC Accessory Apartments Forum.

Maura Brophy is an urban planner and an Associate Director with the Federal City Council. In her current role, she is responsible for managing projects in the organization’s transportation and infrastructure portfolio. Maura holds a MPS in Urban and Regional Planning from Georgetown University, where she completed extensive research on accessory apartments and DC's 2016 zoning revision.